Mushroom growth enhancers and method for preparing same

ABSTRACT

The present invention is a process for preparing growth and nutritional enhancement additives for use with mushroom cultivation and products prepared therefrom. The process includes subprocesses for preparing an activator particle containing ingredients which help maximize growth activity in the fungus and a combination particle which includes activator particles and delayed release nutrient material which helps to sustain optimal growth. The particles produced by the process, namely the activator particle, the combination particle and a method for bringing the particles into contact with mushroom mycelia at the optimum time are also included. The invention is intended to maximize efficient, rapid and healthy growth in commercial mushroom strains.

TECHNICAL FIELD

This invention relates generally to methods for producing nutritionaladditives for biological systems and more particularly to processes forpreparing growth inducing materials and food stuffs for use in growingmushrooms and to the products resulting from the processes.

BACKGROUND ART

"Mushroom" is a generic term which refers to a number of species offungus, in particular those species which are edible. Mushroom growinghas become a multi-billion dollar international industry in recentyears. The industry has pushed hard and long to attempt to discovermethods of growing bigger, more esthetically pleasing, and tastiermushrooms. It has also been a prime object of the industry to discovermethods of growing these mushrooms in the shortest possible period oftime and with the least incidence of diseases and failures.

A typical mushroom crop consists of a number of distinct stages. Themushroom must go through the stages of compost preparation, compostpasteurization, spawn preparation, planting, vegetative development,after which time the environment is "cased" to induce the production offruit, and finally, fruition. The length of time required for each ofthese stages is dependent both upon the type of mushroom to be grown andupon the precise environmental conditions to which the mushroom sporesand mycelia are exposed.

The production of the mushroom spawn for innoculation is one of theinitial stages. Typically, this consists of the preparation of a largenumber of kernals of some member of the wheat family, preferably rye,although millet is also used. The rye kernals are sterilized andprepared and then innoculated with the mycelia of the particular speciesof mushroom desired, typically, in the United States, Agaricus bisporus.The mushroom mycelia are then allowed to proliferate upon the kernels ofgrain until the individual kernels are completely covered by the livingmushroom tissue. The mushroom mycelia-covered kernels which result areknown in the industry as "spawn".

The production of spawn is typically carried out in a commerciallaboratory environment. The sources for mushroom spawn, particularlythose of a specific species, are quite limited. Ordinarily, the spawnavailable for a particular type of mushroom will have less than fiftyoriginal sources throughout the world. Sterility and quality control inthe early stages of spawn production are extremely important.Consequently, the spawn is typically produced in a laboratory thenstored and shipped to the end users, the growers.

Once the grower has received the spawn he is ready to undertake thesecond stage of mushroom growing, the planting of the spawn. The growerhas prepared, and aged to the proper stage, under proper temperature andenvironmental conditions, a bed of compost in which the spawn is to beplanted. This compost has traditionally been the cleanings from horsestables or other similar composts, although modern composts come from avariety of sources. It is necessary to select and treat the compostcarefully so that it has good nutrient content and does not containundue amounts of acid or various chemical and biological inhibitors suchas high ammonia content. High concentrations of chemicals such as acidsor ammonia will hinder the growth of the mushrooms and reduce theefficiency of the operation.

The actual planting consists of distributing the spawn throughout thecompost bed in such a manner that the food contained in the bed isreasonably accessible to each spawn. To achieve this, the spawn grainsare typically evenly distributed over the compost surface and thenmechanically mixed into the compost.

Once the spawn has been planted, it is allowed to vegetate and growunder controlled environmental conditions until it is "cased" and thencontinues to vegetate until the mycelia are ready for fruition. Theamount of time necessary for such vegetative growth is dependent on theprecise environmental conditions, the particular type of mushroom andthe nutrative content of the compost bed. A typical vegetative stageextends between thirty days and thirty-six days.

After the vegetative phase has continued for the appropriate length oftime, approximately twelve to sixteen days, the grower will perform anoperation known as casing. Casing involves spreading a thin layer ofsoil over the compost bed. This soil is kept moist. The bed temperatureis thus reduced for a short period. This temperature reduction has theeffect of causing the mushroom mycelia to fruit or "crop" and thus sendup the actual mushrooms through the casing soil.

The final stage of a mushroom crop is the actual fruition or "cropping".During this stage the mature fungus sends up the fruiting bodies whichare marketed as mushrooms. Each particular colony of fungus will send upfruit when it has reached the proper stage. The actual time frame of thefruition varies throughout the bed. The fruition stage of the croptypically appears about nineteen days after casing and lasts forapproximately four to five weeks.

Of the four main stages of a mushroom crop only the vegetative stage andthe fruition stage are significantly affected by the addition of anutrient additive. The duration of the spawning stage is determinedprimarily by the type and condition of grain used and the particularstrain of mushroom mycelia innoculated onto the grain. The plantingstage is of relatively short duration and can be improved only bymechanical techniques such as improved evenness of distribution of thespawn kernels. The timing of the casing affects the timing of thefruition but this operation is relatively independent of nutrients. Thevegetative and fruition stages, however, and to a certain extent thelater portions of the spawning stage, can be affected significantly bythe addition of biological activators and nutrients to the process.

The basic methods for producing mushroom spawn have been described in anumber of United States patents. These patents include U.S. Pat. No.1,869,517 issued to J. Sinden; U.S. Pat. No. 2,005,365 issued to R.DiGiacinto; U.S. Pat. No. 2,044,861 issued to J. Sinden; and U.S. Pat.No. 3,828,470 issued to B. Stoller. Each of these references relates tothe manner in which mushroom spawn is prepared for the vegetative phase.

U.S. Patents have also issued regarding the method of adding nutrientsor synthetic composts to mushroom cultures to provide for improvedgrowth characteristics. These have included U.S. Pat. No. Re. 22,202reissued to B. Stoller; U.S. Pat. No. 3,560,190 issued to D. Hughes, etal.; and U.S. Pat. No. 3,942,969 issued to A. Carrol, Jr., et al. Eachof these patents relates to the specific content of additives to eitherthe spawn or the compost bed. The additives and processes involved inthese references are intended to increase the production of mushroomsand/or decrease the period of time necessary to grow the mushrooms undercertain conditions.

The subject of mushroom growth activation has also been treated in anumber of scientific articles. These include "Stimulation Of Yield InThe Cultivated Mushroom Via Vegetable Oils" L. C. Schisler, APPLIEDMICROBIOLOGY, July, 1967, pages 844-850; "The Lipids Of ThermophilicFungi: Lipid Composition Comparisons Between Thermophilic and MesophilicFungi" R. O. Mumma, et al, LIPIDS, January, 1970, Volume 5, No. 1, pages100-103; "Thermophilic Fungi: II." R. O. Mumma, et al., LIPIDS, Volume6, No. 6, pages 584-588 (1971); "Thermophilic Fungi: III" R. O. Mumma,et al, LIPIDS, Volume 6, No. 8, pages 589-594 (1971); a masters thesisentitled "Studies On Lipid Metabolism Of Agaricus Bisporus (Lange) Sing.and Compost Lipid Composition" by David E. Smith, Ohio State University(1975); and "Lipid Metabolism Of Mushroom Mycelia" R. Barry Holtz &David E. Smith, MUSHROOM SCIENCE 10, Part 1, pages 437-444 (1979)

The various prior art methods have indeed succeeded in producing higherquality mushrooms in a shorter period of time than the older methods.However, there remains a great deal of room for improvement.

Even a small improvement may result in a substantial increase ofproduction to a mushroom grower. For example, a shortening of thevegetative period by as little as two days will allow the grower toproduce an entire extra crop in under three years. Thus, improvements inthe mushroom techniques and additives are of particular commercialimportance.

The prior art attempts have, in some degree, been aimed at improving thenutrient environment for the mushroom mycelia during the vegetativestage. These have included preparing more readily digestible food stuffsfor the mushroom mycelia and have extended to the use of delayed releasenutrients. However, none of the prior art attempts has directly attackedthe phenomenon of aging within the individual mushroom cells and theconcomitant slowing of metabolic membrane transport mechanisms which caneffect the growth velocity.

BRIEF DESCRIPTION OF THE INVENTION

It is therefore an object of the present invention to provide a processof manufacturing additives for mushroom spawn that will induce the spawnto reach fruition in a shorter period of time than without theadditives.

It is also an object of the present invention to retard and preventpremature aging of the individual fungus cells.

It is another object of the present invention to improve the membranetransport characteristics of the individual mushroom cells such that thecells grow more quickly and more vigorously.

It is yet another object of the present invention to provide an additivedirectly applied to mushroom spawn for providing the spawn with areadily available source of nutrition throughout its early vegetativelife time.

Briefly, the present invention includes (a) a process for manufacturinga combination mushroom spawn activator and delayed release nutrientparticle, (b) the combination particle manufactured thereby, (c) aprecursor activator particle, and (d) a process continuation forutilizing the combination particle in conjunction with mushroom spawn.The combination particle includes a number of activator particles, eachof which is made up of a droplet of easily digestible polyunsaturatedoils, surrounded by a thin vitamin-surfactant layer and amicroencapsulating activated protein layer, and one or more delayedrelease nutrient ("DRN") particles, generally made up of an oil dropencapsulated by an exterior layer of partially denatured protein.

The manufacturing process for the combination particle is a combinationof a sub-process of manufacturing the activator particle and asub-process of combining the activator particle with DRN material intothe combination activator-DRN particle.

The activator particle is manufactured by the sub-process of adding theappropriate polyunsaturated oils, blending thoroughly, adding thesurfactant and vitamin materials, blending again, adding the activatedprotein concentrate with further blending, homogenizing the mixture andspray drying the resulting particles.

A combined activator-DRN particle is then formed by the sub-process ofcoagglomerating an amount of the activator particle and a larger amountby weight of DRN particles materials together with a binder, drying theresultant mixture and asceptically packaging the combination.

The resulting combination activator-DRN particle may then either byadded to compost for mushrooms or, by way of the continuation process,be directly brought into contact with immature spawn prior to planting.

An advantage of the present invention is that the single combinationparticle produced by the process, when added to the spawn or compost,can create a major increase in the efficiency of the mushroom crop.

Another advantage of the present invention is that the membraneactivation substances contained in the activator particle retardpremature aging of the mushroom spawn cells.

A further advantage of the present invention is that the combinationparticle resulting is of proper relative size so that it interfaces wellwith mushroom spawn to provide optimum growth conditions.

Still another advantage of the present invention is that a colony ofmushroom mycelia exposed to the particles produced according to theinvention will exhibit improved growth, vigor and disease resistancecharacteristics over unexposed mycelia.

A further advantage of the present invention is that the particlesproduced may nourish a spawn kernel that is planted in a relativelynutritionally barren volume of compost until the mycelia have grownsufficiently to expand beyond their immediate volume and have ability toreach more remote food sources.

Yet another advantage of the present invention is that the processes ofmanufacture for the various particles are simple and easilyaccomplished.

These and other objects and advantages of the present invention will nodoubt become obvious to those of ordinary skill in the art after havingread the following detailed description of the preferred embodimentswhich are illustrated in the various drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart diagram of a process for manufacturing anactivated spawn mixture in accordance with the present invention.

FIG. 2 is a cross-sectional view of an idealized combinationactivator-DRN particle;

FIG. 3 is a cross-sectional view of an idealized activator particle;

FIG. 4 is a cross-sectional view of an idealized DRN particle; and

FIG. 5 is a cross-sectional view of an idealized single cell of mushroommycelium.

BEST MODE OF CARRYING OUT INVENTION

The present invention includes a process for manufacturing particleswhich are used to activate and encourage the growth of mushroom myceliaand the resulting products thereof. The process includes sub-processesfor the manufacture of activator particles, the coagglomeration of theactivator particles and an amount of DRN particles into a combinationparticle, the preparation of mushroom spawn and the addition of thecombination activator-DRN particles to the mushroom spawn at a timeprior to planting to promote the greatest possible activation and growthof the spawn. The entire process is illustrated in the flow chartdiagram of FIG. 1.

As may be seen by the illustration of FIG. 1, the overall process of thepresent invention includes two subprocesses which may be carried outrelatively independently. The activator particle must be created and themushroom spawn must be grown to the appropriate growth stage for mixingwith the combination particle. Therefore, these independent subprocessesmay take place at various times and the overall process is not affectedby the precise timing or order of these processes.

The sub-process for manufacturing the activator particle is designatedin FIG. 1 by the flow chart boxes labeled A1 through A8. Steps A1through A8 represent the various stages of the preparation of theactivator particle in the presently preferred embodiment. The precisesteps and the order thereof may be altered by the use of slightlydifferent ingredients or by the variation in the times required for eachstep or by altering the degree of mixing involved.

Step A1 in the preparation of the activator particle is the addition, ina common container, of the necessary polyunsaturated oils to becontained in the microencapsulated oil protein particle known as theactivator particle. The polyunsaturated oils utilized in the activatorparticle are primarily triglycerides and phospholipids. In the preferredembodiment the ratio of triglycerides to phospholipids is approximately3.3:1.

Triglycerides are glycerol moieties esterified with three distinct fattyacid chains. The preferred triglycerides are those where each chaincontains approximately eighteen carbon atoms and each chain includes twoor more carbon-carbon double bonds (C═C), that is, the chains are"polyunsaturated".

The triglycerides utilized in the preferred embodiment are mixed speciestriglycerides from any of a number of fat sources. The preferablesources are soybean oil, safflower oil and cottonseed oil, as these oilsare particularly high in polyunsaturated oil content. The organic fattyacids which make up the acid chains in the triglycerides contained inthese oils are primarily Palmitic [Hexadecanoic acid CH₃ (CH₂)14 COOH],Oleic [9 Octadecenioc acid, CH₃ (CH₂)₇ CH:CH (CH₂)₇ COOH] and Linoleic[9, 12 Octadecadienoic acid, CH₃ (CH₂)₄ CH:CH CH:CH (CH₂)₇ COOH] acids.The eighteen carbon polyunsaturated fatty acids such as linoleic acidand linolenic acid [9, 12, 15 Octadecatrienoic acid, CH₃ (CH₂ CH:CH)₃(CH₂)₇ COOH], another component of the triglycerides, are the preferredfatty acid components of the activator particle.

The phospholipids used in step A1 are obtained primarily from naturallecithin. Soybean lecithin is the primary source of the phospholipidsutilized in the activator particle. It is desirable that thephospholipids utilized have a high linoleic acid content. Thephospholipids which are predominant in these lecithin fractions andwhich are the most effective activators and surfactants are phosphatidylcholine and phosphatidyl ethanolamine.

Step A2 is the thorough blending of the polyunsaturated oil additives.Since the phospholipids and triglycerides are reasonably miscible theycan ordinarily be properly blended by the use of ordinary stirring for aperiod of about five minutes.

In Step A3, the surfactant and vitamin membrane stabilizer material isadded. In the preferred embodiment, both the surfactant andstabilization functions are accomplished by the use of a group oforganic chemicals characterized as tocopherols, and preferablyα-tocopheral (vitamin E). A tocopherol solution is added to thepolyunsaturated oils at a concentration of approximately 200 ppm (partsper million). The sources of the tocopherols utilized are commerciallyavailable vitamin supplements and certain natural sources including soyoil fractions, wheat germ oil, and other vegetable oil fractions. Thetocopherols derived from sources other than specific commercial vitaminsupplements will be of a mixed variety. Mixed tocopherols are adequatefor the purposes of the invention although a pure α-tocopherol additivemay have certain superior characteristics regarding membrane activation.

In step A4 the tocopherol additive is thoroughly blended with thepolyunsaturated oils. Since the tocopherol additive and the oils are notentirely miscible, it is necessary to provide agitation during theblending of these components. It has been found that five minutes ofblending with agitation is adequate.

Step A5 is the step wherein the activated protein concentrate is added.The weight ratio of added protein solids to polyunsaturated oil in theresulting mixture is approximately 1.5:1.

The preferred protein concentrates for use in step A5 are water solubleproteins having at least a 92% protein level by weight. It is alsopreferrable that the salt content in the protein concentrate berelatively low, however, some residual calcium salts are allowable.Preferrable protein concentrates for use in the present invention arecalcium caseinate, whey protein concentrates, soy protein concentrates,whey-soy protein co-precipitates and sodium caseinate. Due to theparticular value of calcium to the cell membrane structure of mushroomsprawn, it is preferrable to utilize calcium caseinate.

In step A6 the protein additive is blended with the prior mixture. Sincethe protein is added as a solid to the liquid organic oils, it isnecessary to use low speed agitation and blend the mixture thoroughlyfor a period of approximately fifteen minutes. At the conclusion of stepA6 the various components comprise a liquid-solid suspension.

In step A7 the suspension is homogenized. The homogenization causes thesuspension to be thoroughly blended such that it will not naturallyseparate into distinct layers in a liquid form.

Homogenation in the preferred embodiment is accomplished using a dualstage homogenization pump. This pump uses conventional homogenizationvalves. For the first stage of the homogenization the pressure is set at4.4×10⁴ g/cm (1500 psig) and the second stage is accomplished at apressure setting of 1.5×10⁴ g/cm (500 psig).

The final step in the manufacture of the activator particle is step A8in which the homogenized suspension is formed into small round particlesand spray dried. The spray drying step reduces the moisture content ofthe homogenized suspension and forms the material into microencapsulatedparticles.

The homogenate is spray dried in a nozzle or centrifugal atomizer dryerof standard commercial configuration. It is desirable to reduce thefinal moisture content of the particles in the drying step toapproximately 6%. For a typical feed rate, the inlet temperaturenecessary to accomplish this amount of drying would be approximately150° C. (300° F.).

After the completion of step A8, the activator particle is complete andmay be used independently. The resulting particles are microencapsulatedoil particles with the protein concentrate acting as the encapsulatingsubstance. The vitamin-surfactant layer acts as a surfactant between theprotein layer and the oil drop. The activator particles areapproximately spherical in shape and have a diameter in the neighborhoodof 200 microns (2.0×10⁻² cm). At this point the activator particles arerelatively stable and may be stored until needed.

The DRN particles may be manufactured by any of a number of knownprocesses or may be commercially purchased. The DRN material utilized inthe preferred embodiment of the invetion is a commercially availablenutrient sold as "Spawn Mate III" by Spawn Mate, Inc. of San Jose,Calif. The DRN particle materials may be obtained either in the form ofa heavy slurry of microencapsulated particles or in the form ofparticles. In either form the DRN materials are rewetted and combinedwith the activator particle into the combination activator-DRN particle.This combination particle is manufactured and packaging for shipment insteps C1, C2 and C3 as shown in FIG. 1.

In step C1 the product resulting from the subprocesses A1 through A8 arecombined and coagglomerated with DRN particle materials. The smallrelatively dry spherical activator particles, which are dry are mixed inthe coagglomerating apparatus with either slurried or relatively dry DRNparticles. The DRN particles are ordinarily much larger than theactivator particles. Although none of the particles are actually uniformin size and only an approximation is possible, a typical DRN particlewill have a radius about ten times as large as the radius of anactivator particle. In this storage, the weight ratio of activatorparticle to DRN particle is approximately 1:10. A third ingredient isalso added at this stage, this ingredient being a 6% solution ofmodified food starch which is atomized into contact with the activatorparticles and the DRN particles during the coagglomeration procedure.The starch acts as a binder to hold the combination particle together.The amount of starch solution added is sufficient to bind the otherparticles together while the residual starch content is less than 3% perweight of the entire combination particle. Other binders may also beutilized.

The actual coagglomeration is accomplished by a standard tower typeagglomeration apparatus.

The tower type agglomeration is a large vertical cylindrical tube,typically 6-10 meters (≃19-31 feet) in height and 0.9-1.7 meters (≃3-5feet) in diameter, provided with a variable updraft. The particles areintroduced into the tower at the top. This is ordinarily accomplished bya conveyor or other bulk delivery system. The updraft fan is set suchthat the air stream is sufficiently strong to prevent the activatorparticles and DRN particle materials to sink against the flow. Thebinder material, which is a starch solution in water, is injected intothe agglomerator as a fine mist which is carried by the air currentsinto contact with the particles. The particles thus become wet andsticky and adhere together to form combination particles. When theweight to surface area-cross section ratio becomes sufficient throughcombination the particles fall through the air stream and exit theagglomerator at the bottom. The size and water content of the resultingcombination particles may be adjusted by varying the speed of theupdraft and the concentration and amount of the binder solution.

Alternatively, the coagglomeration step C1, may be accomplished by ablade type agglomerator. This uses a binder solution and either an airstream or mechanical mixing method to cause the individual particles toadhere together while the blade action controls the size of theresulting combination particles.

The combination particle resulting from the coagglomeration step, C1,has a water content in the range of 20% to 25% by weight. Theapproximately spherical resulting particles are combination particleseach having a sieve profile of greater than 80%, +48 Taylor sieve mesh.Thus, the approximately spherical combination particles have diametersin the neighborhood of 500 microns (5.0×10⁻² cm).

The step C2, the combination particles are dried. This step is intendedto reduce the residual moisture content in the combination particles andto make them more usable for storage and shipping and less suseptible tocontamination. A certain amount of heat denaturation, affecting thetertiary structure of the proteins, also takes place during this step.The proteins of the activator particle, being drier, having a lowerspecific heat per particle and being higher quality proteins, aredenatured less than those of the DRN particle.

In the preferred embodiment the drying stage C2 is accomplished on aseries of fluid bed driers. The particle temperatures on the first fluidbed drier are controlled to be approximately 44° C.±3° (110° F.+5°). Onthe second and final fluid bed drier the particle temperatures arecontrolled to be approximately 60° C.±3° (140° F.±5°).

After the drying step has been completed, the combination particles aredry and ready to be packaged and stored. At this stage, the particlesmay be directly applied to compost of mushroom spawn instead ofpackaging. However, if the combination particle is to be packaged orstored it should be packaged asceptically to prevent rot orcontamination.

Step C3 is the asceptic packaging of the combination particle. Since thecombination particle is a nutritionally desirable particle for a greatnumber of bacteria and fungi other than the desired mushroom mycelia, itis necessary to protect the particle from contamination until it isready to be added to the mushroom spawn. Sterilization of the particlesis accomplished in step C2 wherein the drying temperatures are above thethermal death point of most contaminating organisms. However, it isnecessary to make certain that the particle does not becomerecontaminated from the air or other environmental elements with whichit comes in contact. Therefore, in step C3, it is immediately packagedin sterilized and environmentally isolated containers until it is readyfor use. The preferred type of container is a hermetically sealedplastic bag. At this point, the combination particle is ready to beshipped and applied to mushroom spawn at any of a number of stages ofdevelopment of the spawn.

The independent subprocesses which is necessary for the continuationportion of the overall activated spawn process is the actual preparationof the mushroom spawn itself. In FIG. 1 this subprocess is illustratedat steps S1 through S3. The actual growing of spawn is ordinarily doneat a small number of central spawn producing laboratories and will notordinarily be undertaken by the grower.

Step S1 involves preparation of a suitable growth medium for mushroommycelia. This medium is typically made up of a large number of speciallyprepared kernels of the grain family, ordinarily rye or millet. Thekernels are especially prepared by cooking in water in a large kettle orautoclave. A buffering agent such as calcium sulfate (CaSO₄) or calciumcarbonate (CaCO₃) is typically added to counteract chemicals andconditions incurred during the cooking and sterilization procedure. Thegrain is then sterilized by introducing the medium into an autoclave ata temperature greater than the thermal death point of harmful bacteria.Thus, the kernels are particularly well suited for an initial growthmedium for mushroom spores.

In step S2 the kernels are inoculated with the vegetative tissue of theparticular variety of mushroom to be grown, most commonly Agaricusbisporus.

Step S3 is the initial growing of the spawn upon the grain kernels. Inthis step the inoculated kernels are placed in proper environmentalconditions and allowed to grow for approximately 4 days. After thisinitial growing stage has past, the mushroom spawn has reached the stagewhere it is ready to be brought into contact with the combinationactivator-DRN particle to form the activated spawn.

The activated spawn is created when the spawn produced in steps S1through S3 is brought into direct contact with the combinationactivator-DRN particle produced in steps C1 through C3. The stepsutilized in producing an activated spawn ready for planting within agrower's compost bed are illustrated in FIG. 1 as steps AS1 through AS3.

Step AS1 involves the combining of the combination particles with theindividual spawn-rye kernels such that the spawn is in direct contactwith the combination particle. This may be accomplished by ordinarygentle mixing. The preferred method of combining the spawn with thecombination particle is gentle, mechanical stirring. Since the spawnkernels are much larger than the combination activator-DRN particles,each spawn kernel will be surrounded by a large number of particles.

Step AS2 involves placing the activated spawn into optimum growingconditions and allowing it to mature for approximately eight to tendays. This growth period allows the spawn to develop to the stage whereit is ready for planting. The interaction between the spawn and thecombination activator-DRN particle keeps the spawn in an extremelyvigorous growth phase throughout this period. The mycelia will grow andattach to and engulf neighboring combination particles such that theseparticles will remain in proximity to the spawn kernel, now a mushroommycelium colony, even during the agitation of planting.

Step AS3 involves arresting the development of the spawn byrefrigerating it. Under cold temperatures, the mushroom mycelia willbecome essentially metobolically inert and will continue to grow only ata very slow pace. In this condition the spawn may be easily shipped toits final destination and prepared for planting. When the spawn iswarmed up to normal planting temperatures and placed under normal growthconditions again, it will resume growth at the same rate as it had priorto refrigeration in the normal case. The overall effect of therefrigeration is simply to slow down time for the mycelia until it isappropriate to have full growth conditions again.

FIGS. 2 through 6 illustrate idealized conceptions of the variousindividual particles which are created during the process of the presentinvention. Each of the particles formed during the process will varygreatly in shape and size but for the purposes of illustration it isconvenient to think of each type of particle as being uniformlyspherical in shape.

FIG. 2 illustrates the combination activator-DRN particle manufacturedin accordance with the present invention. The combination activator-DRNparticle is referred to by the general reference character 10.

It may be seen in FIG. 2 that the combination particle 10, as seen in anidealized cross section, is made up of a plurality of activatorparticles 12 and a plurality of DRN particles 14. The various individualparticles 12 and 14 which make up the combination particle 10 are heldin position by a binder 16.

In the actual individual combination particle 10, the ratio andarrangement of the subparticles is random. Although the weight ratio ofDRN material 14 is 10:1 to activator material, due to the much greatersize of the DRN particles 14, the number ratio of DRN particles 14 toactivator particles 12 is approximately 1:10. Due to the efficacy of thecoagglomeration step this ratio is usually reasonably maintained in theindividual combination activator-DRN particles. However, the specificarrangement of the sub-particles within the combination particle 10 istotally random. Furthermore, it is unlikely that the particles actuallyproduced by the processes of the present invention will be regularlyspherical in shape. Thus, the illustrations are purely for the purposesof showing the relationship of the subcomponents of the particles andnot to indicate any actual physical situation.

The binder 16 utilized in the preferred combination activator-DRNparticle is a modified food starch solution added during thecoagglomeration step C1. When dried, this food starch forms a nutritiousadhesive holding the subparticles together.

FIG. 3 illustrates a cross-sectional view of an idealized activatorparticle 12 as produced in steps A1 through A8. The activator particleis made up of three distinct layers. The interior portion of theactivator particle 12 is a fat droplet 20. Immediately surrounding thefat droplet 20 is a very thin vitamin-surfactant layer 22. Thevitamin-surfactant layer 22 is ilustrated as being much thicker than itactually is. In the actual particle the vitamin-surfactant layer willactually constitute only a very small portion of the radius of theactivator particle 12. The outer layer of the activator particle 12 isan activated protein layer 24.

Fat droplet 20 is made up of the triglycerides and phospholipids whichare added in step A1 as illustrated in FIG. 1. This droplet 20 is arelatively homogeneous mixture of the long chain polyunsaturatedtriglycerides and the phospholipids. The preferred triglycerides havecarbon chains in the range of C₁₈ length. The chains of thetriglycerides are preferably unsaturated, being at least monounsaturatedand preferrably diunsaturated fatty acids. The triglycerides arepreferably made up of oleic, and linoleic acids. Linolenic acid contentis desirable but difficult and expensive to maintain. The triglyceridescontained within the fatty acid droplet 20 are similar in many ways tothose found within the compost in which the mushroom spawn will beplanted. The major difference between the triglycerides in the fatdroplet 20 and the triglycerides to be found within the compost is thatthose within the fat droplet 20 are much more concentrated and willcontain a much higher percentage of unsaturated and polyunsaturatedtriglycerides than will the compost. This is important because themushroom mycelia can more easily utilize the polyunsaturatedtriglycerides than other long chain fatty acids.

The phospholipids contained in the fat droplet 20 are also similar tofood elements which will be found in the compost into which the mushroomspawn will be deposited. These phospholipids are primarily of the typederived from lecithin. It is important that the phospholipids in fatdroplet 20 contain a high linoleic acid content. The phospholipids areprimarily phosphatidyl choline and phosphatidyl ethanolamine. Thephospholipids contained in the activator particle are such that they aremore easily nutritionally utilized by the mushroom mycelia than arethose of the actual compost.

The vitamin-surfactant layer 22 immediately surrounds the fat droplet20. The vitamin-surfactant layer is made up primarily of mixedtocopherols. α-tocopherol (commonly known as vitamin E) is a majorcomponent of the mixed tocopherols. These mixed tocopherols, derivedprimarily from natural sources such as soy and wheat germ oil fractions,serve the dual purposes of preventing premature aging in the mushroommycelia cell membrane and also serve as a surfactant, or an emulsifierwhich maintains the spatial integrity of the fat droplet within theactivator particle 12. The emulsification function of thevitamin-surfactant layer helps to encapsulate the fat droplet 20 withinthe activator particle 12 and to maintain a separation layer between thefat droplet 20 and the activated protein layer 24.

The activated protein layer 24 is made up primarily of very highconcentration readily assimilated and utilized protein material. Thepreferred protein for the activated protein layer 24 iscalcium-caseinate. This variety of protein is preferred because it isvery easily digestible to the young mushroom mycelia and also becausethe calcium content is valuable as a cofactor for rapid growth of themushroom mycelia. Other protein concentrates will also function as theactivated protein layer but are less preferred. Among the proteinconcentrates which may be used are whey protein concentrates, soybeanconcentrates, sodium caceinate concentrates and whey-soy proteinco-precipitates.

The activated protein layer 24 provides about 60% of the total volume ofthe activator particle 12. Since the activated protein layer 24 providesthe outer surface of the activator particle 12 it will be the initialportion of the particle attacked by the mushroom mycelia.

FIG. 4 illustrates the DRN particle 14. In this idealized view it may beseen that the DRN particle is made up of two distinct components. Thesecomponents are an oil drop 30, and a denatured protein layer 34. Thegreatest portion of the DRN particle is made up of denatured protein.

The oil drop 30 of the DRN particle 14 is a vegetable type oil which maybe readily assimilated and digested by the mushrool cell.

The outer portion of the generally spherical typical DRN particle 14 isthe denatured protein layer 34. This layer is composed of a proteinconcentrate which has been chemically altered such that it is difficultfor a mushroom cell to quickly assimilate and utilize it. The protein indenatured protein layer 34 is partially denatured, that is, altered inits chemical and spatial structure in such a manner that it is moredifficult for the mushroom mycelia to digest it. This is in directcontrast to the protein layer 24 of the activator particle 12 in whichthe protein is specially selected such that the cells may easily utilizeit. The denatured protein layer 34 makes up the great bulk of the DRNparticle 14 and forms an effective barrier between the cell and thedesired oil drop 30.

FIG. 5 illustrates an idealized mushroom cell 40. In this theoreticalview of an individual fungus cell, it may be seen that the cell includesan interior or cytoplasm 42 and a cell membrane 44 also known as aplasma membrane. The cytoplasm 42 composes the majority of the actualliving reproducing tissue of the mushroom cell 40 while the plasmamembrane 44 provides a boundary and a buffer between the outsideenvironment and the cytoplasm 42. This plasma membrane 44 controls theflow of nutrients and other materials into and out of the cytoplasm 42.In this illustration the plasma membrane 44 is shown to bedisproportionately thicker than it would be in the actual cell. Anindividual mushroom cell 40 is of microscopic dimensions.

INDUSTRIAL APPLICABILITY

The preferred embodiment of the present invention is intended to providea healthy, vigorously growing mushroom spawn at the time of plantingwhich maintains its vigorous growth throughout the vegetative phase andproduces high quality mushrooms within a shorter period of time than theprior art. The activator particle 12 may be separately utilized inregard to a mushroom cell 40. These particles serve an independentfunction and, when used in combination with DRN materials, or when thecombination particles 10 are placed in proximity to a spawn kernelparticularly beneficial results are obtained regarding the mushroomgrowth. Each of the ingredients in the various particles have differenteffects on the individual mushroom cell 40 and particularly on theplasma membrane 44. The presence of these additives contained in theactivator particle 12 and the DRN particle 14 have varying effectsthroughout the life cycle of the mushroom mycelia.

The mushroom cell 40 is the outgrowth of spores of the mushroom fungus.During the spawn producing stage, steps S1 through S3 of FIG. 1, thesecells are grown, under as close to theoretically ideal conditions asfeasible, on a nutrient rich medium, usually seed grain such as rye.During this stage, the mushroom colony grows in such a manner that thecells group to form filament-like threads for feeding. These filamentsseek out nutrient sources and deliver nutrients to the interior cells aswell as obtaining nutrients for the cells contained within thefilaments. The amount and type of nutrients entering the individual cell40 and the waste materials expelled are controlled by the plasmamembrane 44. The cell cytoplasm 42 must receive all its nutrients andenergy through the plasma membrane 44.

The manner in which a mushroom cell obtains nutrients is accomplished bythe action of various enzymes associated with the cell upon thenutrients. Some of the enzymes cause the nutrients to be easilytransferred through the plasma membrane 44. The cell is capable ofmanufacturing various enzymes for the specific purpose of chemicallyacting upon particular types of nutrient to which the cell has come incontact. When the cell contacts a particular type of nutrient, forexample, a lipid, the cell will react by producing and secreting anenzyme specifically directed at lipid breakdown. Such a lipid specificenzyme is called a lipase. Different lipases exist for the various typesof lipids which the cell would wish to ingest. For example, theingredients of the fat droplet 20 in the activator particle aretriglycerides and phospholipids. In order to ingest these two varietiesof lipids, the cell would construct and secrete a triglyceride lipaseand a phospholipase. These enzymes would specifically act upon therespective lipids to break down the lipid structure, cause the lipid tobe transferable through the plasma membrane 44 and make the lipidssuitable for energy release within the cytoplasm 42. In this manner, theindividual cell obtains energy from its environment and grows anddivides to create a larger and more vigorous mushroom fungus.

Enzymes are large protein complexes which are biosynthesized by thecells to accelerate the rates of biochemical reactions. Enzymesgenerally serve to catalyze reactions which are necessary or useful tothe cell. Most enzymes are not stored in an intact form by the cell butare instead biosynthesized in response to specific biochemicalinducements. This biosynthesis process consumes time. For example, acell having the genetic ability to synthesize an enzyme to facilitatethe breakdown of complex fats, such as a lipase to break down lipids,will not have preformed lipases stored within the cell. Instead, thecell will respond to the stimulus provided by the presence of lipids inclose proximity by biosynthesizing the breakdown enzyme. The enzymes andother biochemical moieties produced in response to specific stimuli areknown as inducible complexes. Once the stimulus is removed the cellresorbs the protein making up the complex and utilizes the protein forother purposes. However, if the inducible complex has already beeninduced and maintained by the continued presence of stimuli the cell canrespond more rapidly to nutritional stimuli in its environment.Consequently, the growth rate of the individual cell can be greatlyincreased by the continuous exposure of the cell to certain varieties ofnutrients such that it is not necessary for the cell to frequentlyremake or change nutrient enzymes.

One of the functions of the activator particle 12 is to activate themain nutrient reducing enzymes of the cells and to keep them activatedthroughout the growth period of the cells. Since these enzymes will benecessary to break down the energy sources available in the compost bedduring the vegetative stage, it is highly desirable for the cells to bemetabolically prepared to encounter these nutrients. Thus, the readilyutilizable polyunsaturated triglycerides and phospholipids contained inthe fat droplet 20 of the activator particle 12 cause the mushroom cellcoming into contact with these polyunsaturated oils to constructtriglyceride lipases and phospholipid lipases to ingest suchpolyunsaturated oils. When the cells then encounter similar energysources within the compost, they will have the high level of the enzymesrequired to ingest such energy sources. The total growth time of suchactivated cells will be decreased by eliminating the necessity for thecells to produce the necessary enzymes after encountering the nutrient.

Besides inducing the mushroom cells to produce quantities of appropriateenzymes for maximum growth within the compost medium, the activatorparticle 12 has a further purpose of optimizing nutrient transferthrough the plasma membrane 44 and preventing undue aging within themembrane. The materials contained in the vitamin-surfactant layer 22 andthe protein layer 24 of the activator particle 12 serve this purpose.

One of the primary enzymes for transferring energy through the plasmamembrane 44 is an enzyme known as an ATPase. ATP (adenosinetriphosphate) is a primary energy transfer carrier in living cells. AnATPase promotes the function of this energy transport within and throughthe plasma membrane 44. In the mushroom cells the ATPase is such that itis activated by the presence of calcium. Thus, the presence of calciumat the plasma membrane barrier activates this enzyme and promotes theoptimum level of energy transport by virtue of this enzyme. The calciumis provided by the activator particle 12 through the calcium caseinatecontained in the protein layer 24. The calcium caseinate of the proteinlayer 24 thus not only provides a source of highly nutritive protein inthe form of the caseinate but also provides a source of free calciumwhich activates the ATPase for maximum energy transport and mostefficient cell growth.

The vitamin-surfactant layer 22 provides the chemical agents known astocopherols which help minimize the aging and defense mechanisms of theplasma membrane 44.

As a cell grows and ages, the plasma membrane 44 is affected in a numberof ways. One of the deleterious effects of aging is that the structurallipids of the membrane itself are gradually transformed from unsaturatedor polyunsaturated lipids into saturated lipids. Another deleteriouseffect is that waste products which prevent efficient energy andnutrient transfer build up at or near the membrane. A third difficultyis that as the cell ages it will begin to activate defense mechanismsagainst hostile conditions in its environment. In response to suchconditions as an improper pH or the presence of materials toxic to thecell, the cell will build up, near the plasma membrane 44, a group ofstable fats known as ergosterols. These ergosterols lower thepermeability of the membrane 44 and thus help to prevent the influx ofthe toxic substances into the cytoplasm. However, this decrease inpermeability also lowers the influx of nutrients and consequently slowsthe growth rate. These conditions which appear as the cell ages can havea damaging effect upon the activity and growth rate of the mushroomspawn once it has reached the compost and is in the vegetative stage.

The tocopherols, such as α-tocopherol (vitamin E), which make up thevitamin-surfactant layer 22 help to alleviate these problems. Thestructure of tocopherols is such that these chemicals will act asantioxidents and actively compete for available free radicals. Thus, inthe presence of tocopherols, the concentration of free radicals isreduced. The free radical capture proclivities of the tocopherols serveto retard the aging process. The means by which the membrane 44 ages isprimarily accomplished by the reduction of the polyunsaturatedstructural lipids of the membrane 42 to less efficient saturatedstructural lipids. This chemical reduction and saturation isaccomplished by the free radicals in the environment. When theconcentration of free radicals is limited by the presence of tocopherolsthe structural lipids are not attacked to the same degree and a higherconcentration of polyunsaturated structural lipids is retained. It hasbeen shown that the membrane transfer characteristics of the cell aresignificantly improved with polyunsaturated structural lipids ascompared to saturated structural lipids.

By capturing the available free radicals which would ordinarily causethe aging of the cells, the tocopherol maintains better membraneintegrity and obviates the necessity for the cell to synthesizeergosterol. Thus, the cell does not produce the blocking ergosterolswhich lower the membrane transfer characteristics at as rapid a rate asit would were the tocopherols not present. The net result is that therapid growth period of the cell is extended. Since a greater portion ofthe cell life is thus in the condition of youthful vigorous growth, thenet time to maturity or fruition of the fungus is compressed and ittakes less time for the grower to obtain a mushroom crop from cellswhich have been so treated.

The DRN particle provides delayed release nutrition to the mushroomspawn cells. After the cells have been activated by the activatorparticles, they need long term nutrition to avoid falling short of therequired nutritive components and decomposing the enzymes necessary tobreak down the triglycerides and phospholipids in the compost. Snce itwould be prohibitively expensive to continuously provide the cells withthe high quality nutrients contained in the activator particles, the DRNparticles are also placed in close proximity to the spawn to insuremaximum growth characteristics.

The oil drop 30 contained within the DRN particle 14 is a mixture ofvegetable oils containing the same types of phospholipids andtriglycerides as will be found in the fat droplet 20 of the activatorparticle. The components of the oil drop 30 need not be as high inpolyunsaturated fats or as carefully controlled as to quality as thoseof the fat droplet but they are very similar. The action of thecomponents of the oil drop 30 upon the mushroom mycelia are much thesame as those of the fat droplet 20. By the time the mycelia havereached the stage wherein they can effectively breakdown the denaturedprotein layer 34 of the DRN particle 14 and penetrate to the oil drop30, it is likely that the available activator particles 12, which themycelia will preferentially attack, will be depleted. Thus, thetriglycerides, phospholipids and other polyunsaturated fats and oils inthe oil drop 30 will re-activate or continue to activate thetriglyceride lipases and phospholipases of the cells and to keep thecells activated such that they will attack the oils and fats of thistype to be found within the compost as well as supplying immediategrowth nutrients to the cells.

The effect of the partial denaturation of the DRN particle 14 is thatthe protein of the denatured protein layer 34 is much less accessible tothe mushroom cell for ingestion. Thus, the mushroom will selectivelyseek more easily absorbed energy sources such as the protein layer 24 ofthe activator particle before attacking the DRN particle 14. However,over the course of time the denatured protein will be broken downenzymatically. The denatured protein thus becomes partially usable as anutrient source in time.

The purpose of the denatured protein and the DRN particle is to providelong term energy sources for the mushroom mycelia. As the cells andmycelia expand and grow, the capacity to attack the DRN particlesincreases. Furthermore, as time passes, the availability of easilyabsorbed nutrients such as the activator particle 12 is reduced. The useof the DRN particles 14 insures that an energy source which may beinitially provided at the time of the planting or at the time of theactivation of the spawn, will still be available at points well advancedinto the vegetative stage and even into the fruition stage. Since thedenatured protein layer 34 is not attacked in the initial stages ofgrowth, it insures that high energy, rapid growth and fruition nutrientssuch as those contained in the oil drop 30 will still be available atthe time of the late vegetative stage and the fruition stage.

By placing the combination activator-DRN particle 10 in proximity to thespawn kernel 52 at an early growth stage as in step AS1, the spawn isinduced to reach an activated, vigorous growth stage and to maintainthat growth throughout its life span to the fruition stage. Thus,planting or "spawning" a spawn kernel which has been surrounded bycombination activator-DRN particles 10 in an activated spawn complexwill result in a vigorously growing spawn provided with a ready nutrientsource. The combination particles 10 will keep the spawn satisfied andvigorously growing until such time that it has reached sufficient sizeto profitably seek out and consume the nutrients available in thecompost. Thus, the activated spawn which has an available supply ofcombination activator-DRN particles 14 will grow more vigorously andrapidly than ordinary spawn or spawn provided only with a DRN particle14. This increased growth can result in a shorter vegetative period, alonger fruition period, and a greater overall production of mushrooms.

It may be seen that the activator particle 12, by itself, may be appliedto mushroom mycelia to increase growth characteristics. This addition isless efficient and economical than the combination with the DRN particlebut is nonetheless valuable in maintaining an activated spawn withoptimal plasma membrane characteristics.

The various steps of the process for manufacturing the spawn complex maybe varied slightly or selectively rearranged without affecting theresult. Furthermore, the specific ingredients utilized in the processand resulting in the activator particle and the DRN particle, as well asthe binders, may be altered to accomplish specific desired purposes.

Although the present invention has been described in terms of thepresently preferred embodiment, it is to be understood that suchdisclosure is not to be interpreted as limiting. Various alterations andmodifications will no doubt become apparent to those skilled in the artafter having read the above disclosure. Accordingly, it is intended thatthe appended claims be interpreted as covering all alterations andmodifications as fall within the true spirit and scope of the invention.

What is claimed is:
 1. A method of preparing a biological activator andnutrient material for use with mushroom cultures, in stepscomprising:preparing a plurality of activator particles, said activatorparticles being adapted to induce enzyme synthesis within the cell andsaid particles being generally spherical in shape and including an innercore of at least one readily assimilable lipid material surrounded by alayer of at least one antioxidant-surfactant, saidantioxidant-surfactant being adapted to slow cellular aging byinhibiting free radial formation, and microencapsulated by an outerlayer of activated protein said activated protein being easilyaccessible to nascent mushroom mycelium; coagglomerating an amount ofthe activator particles with a larger amount by weight of a delayedreleased nutrient material in the presence of a binding agent to formdiscrete combined particles of relatively small size, said delayedreleased nutrient material being in the form of particles, approximatelyone thousand times larger in size than the activator particles, andincluding a lipid droplet microencapsulated by a layer of partiallydenatured protein solids, said protein solids being less accessible tosaid mushroom mycelium such that said mycelium will preferentiallyattack the activator particles; drying the resulting coagglomeratedparticles; and contacting said coagglomerated particles with mushroomspawn.
 2. The method of preparing as recited in claim 1, wherein,thepreparation of an activator particle includes the substeps;A1-addingliquid lipid and fatty acid materials to a common container, -thoroughblending, A3-adding antioxidant and surfactant materials, A4-thoroughblending, A5-adding protein concentrate in solid form, A6-thoroughblending, A7-homogenizing the entire mixture, and A8-spray drying thehomogenate to form small particles in which the protein concentratemicroencapsulates the other ingredients.
 3. The method of preparing asrecited in claim 2 wherein,the liquid lipid and fatty acid materialsadded in substep A1 include phospholipids and triglycerides, saidphospholipids including fractions from natural lecithin containing ahigh linoleic acid content, and said triglycerides including asignificant percentage of unsaturated and polyunsaturated triglycerides.4. The method of preparing as recited in claim 3 wherein saidphospholipids primarily include phosphotidyl choline and phosphotidytlethanolamine.
 5. The method of preparing as recited in claim 2wherein,said antioxidant materials and surfactant materials added insubstep A3 are a collection of mixed tocopherols, said mixed tocopherolsincluding as a primary component alpha tocopherol, said mixedtocopherols being added in an amount that is substantially less than theamount of said lipid and fatty acid materials added in substep A1. 6.The method of preparing as recited in claim 2 whereinsaid proteinconcentrate in solid form added in step A5 includes at least a 92%protein concentration by weight of water soluble protein.
 7. The methodof preparing as recited in claim 6 whereinsaid protein concentrate insolid form includes as a primary component a protein concentrateselected from the group consisting of calcium caseinate, whey proteinconcentrates, soy protein concentrates, whey-soy protein coprecipitatesand sodium caseinate.
 8. The method of preparing as recited in claim 6whereinsaid protein concentrate is comprised primarily of calciumcaseinate, said calcium component thereof being adapted to inducecellular ATPase.
 9. The method of preparing as recited in claim 2whereinsaid homogenizing substep, A7, includes a two step homogenizationin a dual stage homogenization pump.
 10. The method of preparing asrecited in claim 2 wherein,said spray drying substep A8, is accomplishedsuch that the maximum temperature of said particles during said spraydrying substep does not reach a point where a significant amount of theprotein concentrate is thermally denatured, and the residual moisturecontent of said particles is reduced to less than six percent.
 11. Themethod of preparing as recited in claim 1 whereinthe driedcoagglomerated material is asceptically packaged.
 12. The method ofpreparing as recited in claim 1 whereinthe binding agent utilized in thecoagglomeration step is a dilute food starch solution.
 13. The method ofpreparing as recited in claim 1 and further including thesubsteps;bringing said coagglomerated particles into close contact withpartially grown mushroom spawn, vegetating said mushroom spawn incontact with said combination particles under closely controlledenvironmental conditions, and utilizing said spawn to grow therefrommushroom crops.
 14. The method of preparing as recited in claim 13whereinsaid mushroom spawn has been innoculated onto seed grainapproximately four days before being put into proximity with saidcoagglomerated particles.
 15. A growth inducing additive for use withmushroom fungus comprising:a small radius, approximately sphericalactivator particle, said activator particle being adapted to induceenzyme synthesis within the cell and having a core of high food valueliquid lipids, surrounded by a thin layer of antioxidant-surfactantmaterial, said antioxidant-surfactant material being adapted to reducecell aging by inhibiting free radical formation, and including mixedtocopherols, which materials are in turn microencapsulated by anexterior layer of activated protein solids, said protein solids having aprotein concentration in excess of ninety-two percent by weight and saidprotein being water soluble, and being readily utilizable by themushroom mycelium whereby the mycelium will preferentially attack theactivator particles as a food source.
 16. The additive material asrecited in claim 15 wherein,the liquid lipids include phospholipids,said phospholipids including fractions from natural lecithin containinga high linoleic acid content and triglycerides, said triglyceridescontaining a substantial percentage of unsaturated and polyunsaturatedtriglycerides, and said mixed tocopherols include as a primary componentalpha tocopherol.
 17. The additive material as recited in claim 15whereinthe protein solids include as a primary component thereof aprotein concentrate selected from the group consisting of calciumcaseinate, whey protein concentrates, soy protein concentrates, whey-soyprotein coprecipitates and sodium caseinate.
 18. The additive materialas recited in claim 17 whereinsaid protein concentrate is comprisedprimarily of calcium caseinate.
 19. The additive material as recited inclaim 15 whereinthe weight ratio of the protein concentrate to theliquid lipids is approximately 3:2 and the relative weight of thevitamin-surfactant materials is neglegible.
 20. A growth induciveadditive for use with fungus cultures in combination particlescomprising:a plurality of activator particles, said activator particlesadapted to stimulate immature mushroom mycelium and comprising a lipidcore, surrounded by an antioxidant-surfactant layer, saidantioxidant-surfactant layer including one or more naturally occuringtocopherols and adapted to retard cellular aging, and which is in turnmicroencapsulated by an activated protein outer shell, said outer shellbeing composed primarily of calcium caseinate; a plurality of delayedrelease nutrient particles, comprising a lipid core surrounded by ashell of denatured protein, said delayed release nutrient particlesbeing adapted to provide a long term food source to the maturemycelium;and a binding agent to hold the delayed released nutrientparticles in close proximity with the activator particles, said bindingagent comprising a dilute solution of food starch.
 21. The growthinducing additive of claim 20 whereinthe combination particles areapproximately spherical in shape, with a water content of from 20% to25% by weight and a diameter of approximately 500 microns, and containsaid activator particles and said delayed release nutrient particles ina number ratio of approximately 10 to 1.